Method of manufacturing electric bulbs and bulb blanks for use therein



Dec. 11, 1928.

c. c. BQHNER METHOD OF MANUFACTURING ELECTRIC BULBS AND BULB BLANKS FOR USE THEREIN Filed Feb. 25, 1927 ATTORNEY Patented Dec. 11, 1928.

UNITED STATES PATENT OFFICE.

CLYDE C. BOHNER, OF MAPLEWOOD, NEW JERSEY, ASSIGNOR TO TUNG-SOL-LAMP WORKS, OE NEWARK, NEW JERSEY, A CORPORATION OF NEW JERSEY.

METHOD OF MANUFACTURING ELECTRIC BULBS AND BULB EBLANKS FOR USE THEREIN.

Application filed February 25, 1927. Serial No. 170,768.

This invention relates to electric bulbs and their manufacture.

The" object of the invention generally is a noval and improved method of manufacturing electric bulbs, and the invention also resides in a novel and improved bulb blank for use in the manufacture thereof. More particularly the object of the invention is to facilitate and expedite the assembling and sealing-in operations with resulting marked economy of time and labor in the manufacture, together with a substantial saving in glass or bulb material used. A further object is the elimination of strains in the seal between the mounts and the glass bulbs and the consequent reduction in breakage or shrinkage. For a better understanding of the invention, reference may be hadto the accompanying drawing, wherein:

Fig. 1 is a side sectional view of a head of a sealing-in machine with my novel electric bulb supported thereby ready for the sealing-in operations,

Fig. 2 is a view similar to Fig. 1 indicatin a step in the sealing-in operation with certain parts of the head omitted for convenience in illustration,

Fig. 3 is another view indicating a further step in the sealing-in of the bulb,

Fig. 4 is a indicating a sealed-in bulb just before removal from the machine, and

Fig. 5 is anenlarged view partly insection of a part of the mount holder.

The invention relates particularly to the gravity method of sealing in mounts to glass bulbs, wherein the neck of the bulb 1s melted in line with the mount flange and caused to collapse thereupon, the surplus neck being pulled or falling by gravity and thereby tending to sever itself from the mount seal and the severing operation being expedited by suitable air pressure introduced at the proper time and place within the bulb neck. In prior practice the sealing-in operation has been carried on in such manner and under such conditions as to require a comparatively large time for each sealingin operation, and moreover there have been large breakages or shrinkage due to imperfect sealsa-nd to unavoidable strains being set up in the glass seals formed according to former practice. For example, it has been the practice heretofore to assemble the mount in the bulb with the fiange or flare of the mount in quite close proximity to the interior" wall of the bulb neck, the latter bemg very heavy and substantially thicker than the flares to which they are sealed, with the result that considerable and undue time is required to soften and fuse the bulb necks upon the flares and after fusion and sealing to the flaresto sever-the surplus necks from the seals. Also, there remains a comparatively large mass of heated glass at each seal in which strains are set u I and cause an undue breakage or shri age. In accordance with my invention and referring particularly to Fig. 1,..I form in the neck 3 of the electric bulb 1 and in the plane of the seal which is to be effected, an expanded or bulged out part 2, this being effected previously to the assembly on the sealing-in head of the machine and preferably during the original manufacture of the electric bulb, whether blown or molded The Walls of the bulb neck 3 are necessarily much thicker and heavier than the bulbous or enlarged part of the electric bulb, and the forming of the expanded part 2 of the neck results in the walls of the part 2 being substantially thinner than the other parts of the neck, the thinnest portion'of the bulbous part 2 preferably being not reater than half the thickness of the wall 0 neck 3. A standard form of sealing-in head is indicated including the bulb holder 4 and a mount holder 5, the mount holder 5 projecting up into or engaging the flare of the mount .6. The holders 4 and 5 rotates of course together, as'is usual in sealing-in machines.

8 and projecting freely down into the hollow stem 9 of the sealing-in head, and is provided with an enlargement 10 having a shoulder 95 and these external-threads are shaved off at 100 11 to provide a passage or passages between the tubular holder 5 and the stem 9 for free air flow up the annular. chamber 12, the latter being formed between the part 10 and the externally threaded part of holder 5. 05

The enlargement 10 of mount holder 5 is provided with circular shoulders or steps 15 on its upper side. Oblique openings 13 lead from chamber 12 to the interior of member 5 and similar oblique passages 14 lead from the 110 The mount holder 5 is in the form of a hollow metallic tube, closed at its lower end interior to the outside just above the.

" panded and thinned part 2 of the bulb neck and the burners 16 are adjusted to direct the heating flames against the largest diameter of the expanded part 2 of the neck and approximately in the direction of the flange 6. With these adjustments made, the sealing-in head including the supports 4.- and 5 is rotated about an axis in line with the mount 6, and the flames from the blow pipes or burners 16 playing upon the expanded and thinned walls of the part 2 of the neck, very quickly soften the glass of part 2 in line with flange 6 and cause the gradual collapsing of the thinned part of the neck 2 radially inwards. toward the flare flange 6. At the same time the neck 3 falls by gravity and stretches the softened part 2, thereby causing a further thinning of the same. and collapsing of the part2 of the neck take place very quickly, and the seal is effected when the softened neck engages and is welded to the edge of flange 6. The stretched part 2 also collapses upon the circular shoulders 15, as indicated in Fig. 2.

Upon the collapsing of the part 2 upon the flare flange 6, and the circular shoulders 15,

the heating flames are brought to bear upon; part 2 below the flange 6', asv

the collapsed indicated in Fig. 3, and a small air pressure is introduced into the chamber between the part 10 and the flare flange 6, as for example up through part 9 to chamber 12 and then through the openings 14 and 15, as indicated by arrows in Figs. 3 and 5, which air pressure functions to blow out the surplus part of the thinned and stretched out portion of the neck into a thin bubble 2, the latter under the influence of the small breathing air pressure and. heat being very quickly severedapproximately in line with the flames. The severed parts of the bubble roll upon the adjacent glass parts, the upper portion forming a small bead like part 17 on the exterior of the seal, as indicated in Fig. 4. The bulb 1 is now ready to be removed from the machine and the mount 6 adjusted in the usual manner.

It is understood that the standard sealingin machine is used and that the heating and softening of the bulb part 2 is eflected in stages, there usually being provided two or three sets of blow pipes at two or three stages or positions of the machine respectively,the sealing-in head being carried The softening and stretching successively to these positions to effect the gradual heating, softening and collapsing of resulting from my invention above described,

as compared with the prior practice. The sealing-in operation is speeded up on an average of 2530% with a corresponding savingin time and labor. This speeding-up and saving in time is due to the comparative thinness of the original wall 2 to be heated up, to the stretchingand still further thining out thereof when it is caused to collapse upon the flares, and to the thinness of the collapsed part which requires a shorter time for the blowing out and severing operation. A large drop of the surplus neck 3 is necessary on acount of the large clearance between the flange 6 and the outer portion of the part 2, which results in the thinning and attenuation of the collapsed part 2, and the heating and collapsing operation is substan- ;with heavier seals,-perhaps also to the {Iworkin of the glass during its stretching and collapsing upon the flare flange 6.

Also there is a substantial saving in glass due to the fact that a shorter superflous part 3 of the neck is required to eflect the stretching and collapsing by gravity; as for example a saving of 710% of the glass necessary to form the bulb may be effected as compared with prior practice.

Having thus described my invention, what I claim and desire to protect by Letters Patent is:

1. The method of manufacturing electric bulbs which consists in forming in the elongated neck of a bulb blank and in the plane of the seal and bulbous'ring to cause a thinning of'the glass walls thereat, assembling a mount within the bulb blank with the sealing flange of the mount disposed in the plane of the bulbous ring and then heat-ing the latter to cause it to collapse upon and become welded to the flange while the lower part of the neck causes a still further thinning of the glass walls in the plane of the seal by the stretching thereof.

2. A method of manufacturing electric bulbs which consists in forming in the elongated neck of a bulb blank and in the plane of the seal, a bulged out ring to cause the thinning of the walls thereof, assembling amount within the blank with the mount flange disposed in the plane of the ring and supporting the mount by means of a support having a circular shoulder member disposed at a point removed from the upper end thereof, then heating the bulged out ring and the flange and causing the ring to collapse thereupon and upon the circular shoulder While the lower part of the neck falls by gravity to stretch and cause a furtherthinning of the walls, and then simultaneously heating the stretched neck part and directing air pressure between the flange and the circular shoulder for the purpose of severing the bulb from the surplus neck.

3. The method of manufacturing electric bulbs which consists in positioning a mount within a bulb blank havinga bulbous ring formed in the neck thereof and in the plane of the seal with the securing flange of the mount disposed in the plane of said bulbous ring, uniformly heating and softening the bulged out part of the neck to cause the same to collapse upon the flange and upon a circular support for the mount removed from the flange, while the non-bulged surpluspart of the neck descends by gravity and causes a stretching and a further thinning of the bulged out part of the neck, and then simultaneously heating the stretched part of the neck below the flange and directing air pressure between the flange and the circular sup-v port for severing the bulb from the surplus 85 neck.

4. The method of manufacturing electric bulbs which consists in positioning a mount within a bulb blank having a bulbous ring gradual largest diameter of the bulged out part of the neck, and then uniformly heating and softening the bluged out part of the neck to cause the same to collapse upon the flange while the non-bulged surplus part of the neck descends by avity and causes a stretching and working of the bulged out part of the neck.

6. A bulb blank for use in forming electric bulbs including an elongated neck portion, an enlarged ,mount containing portion, the neck portion containing a bulged out and thinned ring art in the plane of the seal.

7. A glass bulb blank for use in making electric bulbs including an enlarged portion for housing the electric conductors, an elongated neck portion made integrally therewith and abulged out ring part formed in the neck in the plane of the seal and'adjacent the enlarged portion.

In testimony whereof, I have signed my name to this specification.

CLYDE o. BOHhIER.

CERTIFICATE OF GQRRECTEON.

Patent No. 1,694,368.

CLYDE C.

Granted December 11, 1928, to

BOH-HNER.

it is hereby certified that error appears in the printed specification of the .above numbered patent requiring correction as ioilows: Page 1, line 4, ior the word "nova!" read "novel"; line 39, before the Word"'indicating" insert the I word "view"; line 89, for the word "rotates" read "rotate", and line 3%, aiter the word "up" insert the word "to"; page 2, line a, ior the word "tiara-s" read "Hare", and line 16, heiore the word "flange" insert the Word "iiare"; same page, line iii, ciairn 1, ion the word "and" read "a"; and that the said horrors harem shoiiid'he read with these correction therein that the same may coiiioriii to the record oi the case in the Patent @iiice. Signet"; and sealed this ihth day oi ianuery,

ih ii hi. .i. iiioore, hetihg ilonauissioner oi reroute. 

